Coupled multielectrode array sensors (CMAS) (see U.S. Pat. No. 6,683,463, No. 6,132,593, and No. 7180309) and other electrochemical sensors for corrosion monitoring are subject to the bridging effect of the formation of electron-conducting deposits that causes the short-circuiting among the sensing electrodes [see S. Papavinasam, “Electrochemical Techniques for Corrosion Monitoring,” in “Corrosion Monitoring Techniques,” L. Yang, ed., Woodhead Publishing, Success, UK (2008), Section 3.8.3 and pages 77 to 79]. These electron-conducting deposits may be formed by the corrosion of iron in an environment containing hydrogen sulfide (H2S), because the corrosion product (such as FeS) is a semiconductor material. When the sensing electrodes are short circuited, the corrosion current cannot be accurately derived by the current that is measured by the sensor instrument [see Lietai Yang, “Multielectrode Systems,” in “Corrosion Monitoring Techniques,” L. Yang, ed., Woodhead Publishing, Success, UK, (2008), Section 8.8.2]. Thus the sensor instrument cannot effectively measure the corrosion rate. A method to minimize the bridging effect is to increase the distance between the electrodes. Because of the size of the probes and the space of the measurement environment where the probe is installed, there is always a limit for the distance between the electrodes. This is especially true for the CMAS probes, because of the many electrodes it has. Another approach to minimize the bridging effect, in the case of a CMAS probe, is to reduce the resistance of the measuring circuit in the sensor instruments. However, there are challenges in the reduction of the resistance in the sensor instrument when the bridging effect is severe. This invention is related to the separation of the active sensing surface areas of the electrodes to avoid the formation of a continuous layer of electron-conducting deposits along the path between any pairs of the electrodes.